Function initialize

examples/pde/boltzmann_cfd.cpp:201–246

* @brief Initializes internal values used for computation * */

 *
 */
void initialize(Simulation& sim) {
    auto& ux    = sim.ux;
    auto& uy    = sim.uy;
    auto& rho   = sim.rho;
    auto& sigma = sim.sigma;
    auto& f     = sim.f;
    auto& feq   = sim.feq;

    auto& ex   = sim.ex;
    auto& ey   = sim.ey;
    auto& wt   = sim.wt;
    auto& ex_  = sim.ex_;
    auto& ey_  = sim.ey_;
    auto& ex_T = sim.ex_T;
    auto& ey_T = sim.ey_T;
    auto& wt_T = sim.wt_T;

    auto density  = sim.density;
    auto velocity = sim.velocity;
    auto xcount   = sim.grid_width;
    auto ycount   = sim.grid_height;

    ex = af::array(1, 1, 9, ex_vals);
    ey = af::array(1, 1, 9, ey_vals);
    wt = af::array(1, 1, 9, wt_vals);

    ex_T = af::array(1, 9, ex_vals);
    ey_T = af::array(1, 9, ey_vals);
    wt_T = af::moddims(wt, af::dim4(1, 9));

    rho   = af::constant(density, xcount, ycount, f32);
    sigma = af::constant(0, xcount, ycount, f32);

    f = af::constant(0, xcount, ycount, 9, f32);

    ex_ = af::tile(ex, xcount, ycount, 1);
    ey_ = af::tile(ey, xcount, ycount, 1);

    // Initialization of the distribution function
    auto edotu = ex_ * ux + ey_ * uy;
    auto udotu = ux * ux + uy * uy;

    feq = rho * wt *
          ((edotu * edotu * 4.5f) - (udotu * 1.5f) + (edotu * 3.0f) + 1.0f);
    f = feq;
}

/**
 * @brief Updates the particle distribution functions for the new simulation